Work-mounting means



July 12, 1949. T. A. KESTELL 2,475,900

* WORK-MOUNTING MEANS Filed Nov. 19, 1945 I v 4 Sh eets-She et 1 July 12, 1949. T. A. KESTELL 2,475,900

WORK-MOUNTING MEANS v I Filed Nov. 19, 1945 4 $heets-Sheef2 I WORK-MOUNTING MEANS July 12, 1949. Q ,T. A. KESTELL 2,475,900

' WORK-MOUNTING MEANS Filed Nov. 19, 1945 4Sheets-$heet 4 s In! Patented July 12, 1949 UNITED "STATES WORK-MOUNTING MEANS Thomas Aubrey Kestell, Thurmaston, England,

,assignor to .Power Jets (Researchc Develop .ment) Limited, London, England 7 {Application November 19, 1945, Serial No. 629,405 a In Great Britain February 28, 1945 (C1. Sir-237') v 8 Claims. 1

The present inventionrelates to improvements in means for mounting the work, for example for grinding, milling, turning, .or like operations, and is of particular application for example in the profiling of turbine blades or any other work in which a high degree in the accuracy and uniiormity of the profile is necessary.

In particular, the Work-mounting means according to the invention is applicable for use with the profiling machine described in copending application Serial N 0. 611,853, filtedAugust 21, 1945.

The object of the invention is to provide workmounting means which will ensure that the Work whilst rotatable is held very exactly during the required operation, and that each work piece of a plurality simultaneously operated upon is held in the same position so as to permit high accuracy of profile to be attained. In particular, where the axis of rotation of the work is required to oscillate, or for other reason it may be desirable to provide work-mounting means which afford accurate and firm support without the use of a stationary tailstock ,or equivalent second work support, i. e. so that the work is held in an overhung manner, it is our object to meet such a requirement.

With this and other objects in view the workmounting means according to the invention comprises a plate adapted to besecured to and rotate with a rotatable workshaft, means for securing the work to said plate, said workbeingradially spaced from the axis of rotation and provided with means adapted to secure the Work rigidly to an axially-directed extension of said plate, the work thus being secured in two axially-spaced regions, and relying for itssupport mainly on the plate with which it rotates.

By way of example, preferred embodiments of the invention are described hereunder with the aid of the accompanying drawings, in which:

Figure 1 is a front elevation of one form of embodiment; v

Figure 2 is a plan view;

Figure 3 is a partly diagrammatic section on the line JK of Figure 1 with the work turned through 90 i Figure 4 is an enlarged detail View;

Figure 5 is a front elevation-of a second form of embodiment;

Figure 6 is an enlarged detail view;

Figure '7 is a part section on the line LM of Figure 5.

In Figures 1-4, which represent one form of embodiment of the invention as applied to a mandrel intended for operating on the external convex face of for example-a turbine blade, a back plate 2 is secured to a flange 3 of a work shaft 4 and is centralised by a spigot 46 on the said plate 2 and locating in a recess H in the work shaft 4. The mandrel I is located by its conical extension in a conical recess 8 in the plate 2 and is held in engagement thereto by screw 9 and is supported by a tail center 18. The outer surface It of the mandrel I is profiled to correspond with the internal profile of the blade ii. The said blade 6 is clamped at its left-hand (tip) by jaws l2, l3 adapted to slide in a recess M in the plate 2 and clamped together by means of a spindle l5 which is threaded left-handedly on its upper portion and ri'ght-handedly on its lower portion, these threads'engaging with corresponding right-hand and left-hand threads in the jaws l2, and |3 which are centralised by a spring loaded ball 50 fitting into a recess I! in the spindle l5. s

The spindle l5 has squared extensions |8 adapted to take a standard boxkey. On rotation of the spindle l5 the jaws |2, |3. move together or apart due to the left-hand and right-hand threads. If either jaw contacts a blade 6 in advance of the other jaw, unequal clamping is avoided by the fact that the spindle I5 can move lengthwise against the resistance of the spring loaded ball 50 and consequently brings the second jaw into contact with the said blade 6 without giving any further increment to the first jaw which is already in contact.

The blade 6 is located lengthwise by being manually held in contact with a pin I9 in the mandrel during the clamping operation.

The blade is clamped at its right hand, i. e. at the root by jaws 2B and 2| which are mounted on pins 22, 23'journal1ed in a sliding sleeve 24. The said jaws have tails 25 which are forced outwardly by a wedging action of the conical collar 21, which is freely located on the sleeve 24. Lengthwise movement of the collar 21 is obtained by means of a nut 28 in engagement with a corresponding threaded portion of sleeve 24. Equal pressures of the jaws 20, 2| on the blades 6 is effected by the free location of collar 21 on the sleeve 24.

When nut 28 is unscrewedthe collar 27 is held in engagement with said nut by spring 29 and consequently moves towards the right and jaws 20, 2| are then lifted out of contact with the blade 6 by the reaction of spring 29 acting against collar 30 which engages at its abutment face 3| on the jaws 20, 2|. In this position the whole of the clamping mechanism mounted on sleeve 24 is free 3 to be moved to the right away from the blade 6 which is then free to be lifted clear from both sets ofjaws l2, l3 and 20, 2|.

In Figs. -7 which represent a second form of embodiment as applied to a chuck intended for operating on the internal concave face of, for example, a turbine blade, a back plate 6| rigid with an annular extension 62 is centrally located by a spigot 58 and is secured to the workshaft 4 by means of bolts 70. Mounted in the plate 6 1 is a fixed jaw 69 and a sliding jaw '61 clamped by a collar screw 68, both jaws being serrated to correspond with the root serrations of blade t. On either side of the tip of bladeB are two sliding plungers 74, which are held away from the blades by light leaf springs 77.

A cover 64 rigid with the annular extensions 62 carries flat springs 73 which are brought into contact with the ends of the plungers 14, 75, when cover 64 is rotated. The members 62 and a ring 63 have semicircular recesses engaging with a portion of the plungers 74, 75, the ring 63 being carried between the annular extension 62 and the cover 64, the members 52, 64, being held -together by means of studs '65 and nuts 66.

Slots in the cover B4 permit it to be given a partial rotation, and when this rotation is in a clockwise direction, springs 73 will be 'moved into an inoperative position relative to plunger "H5 in which case the latter will be forced outwardly by spring 71. The blade 6 will then be clamped at its root between the jaws 67, 69.

The cover 66 is then given a smaller partial rotation anticlockwise thus bringing the 'leaf springs 73 into engagement with the plungers M, 15 which are forced into engagement with the tip of blade 6, spring i3 being stronger than spring 17.

When the cover 6 3 is clamped by nuts Gfipring 63 is forced into contact with the lplungers 7'4, 15, thus holding them rigidly in position.

"The preferred forms of embodiment hereinabove described permit two or more blades or other work pieces to be operated on simultaneously and also enable every workpiece to be held firmly and in correct location.

I claim:

1. Apparatus Ior rotatably mounting a pluralityof workpieces for profiling operations, said apparatus comprising a single plate havingan axial- 1y directed extension and adapted to be secured to and rotate with a rotatable workshaft, radially movable clamping elements for securing each workpiece in the region of one of its extremities to said .plate and means for applying pressure to said elements in a substantially radial direction only, all the workpieces being circumferentially spaced from one another around said shaft and radially spaced from their axis of rotation, and means for holding the other extremity of each workpiece rigid with said axial extension of said plate, each workpiece being thereby -secured in two axially spaced regions :and supported mainly on said plate.

2. Apparatus according to claim '1 wherein the clamping elements are associated with a membe'r which is freely movable radially whereby upon premature contact of one clamping element-for one workpiece with said "workpiece said "member is moved radially to bring the other clamping elements for said workpiece into contact with said workpiece.

3. Apparatus according to claim 1 wherein said clamping elements comprise a pair of radially movable jaws for holding between them part of a workpiece, the gripping faces of said jaws havinga profile which corresponds with the profile of said part.

'4. Apparatus according to claim 1 wherein at least some of said clamping elements are pivotably mounted, said apparatus further comprising means to urge one extremity of a pivotable clamping element radially outwards whereby the other extremity of said element is urged radially inwards against a workpiece.

5. Apparatus according to claim 4 wherein the said .pivotable clamping elements are mounted on an axially slidable sleeve, said apparatus further comprising a conical collar freely mounted on said sleeve and means for moving said collar axially along said sleeve to urge one extremity of a pivotable element radially outwards.

6. Apparatus according to claim 1 comprising a radially extending and radially movable spindle of which one part has an external left-hand thread and another part has an external righthand thread, said clamping elements comprising a pair of oppositely and radially slidable law members of which one has an internal left-hand thread and the other has an internal right-hand thread, said jaws engaging respectively with said parts of the spindle, and means engaging with said spindle to centralize the jaws.

'7. Apparatus according to claim 1 wherein said clamping elements comprise a plurality of resiliently urged radially movable 'plungers, and means for adjustably fixing said plungers at any desired radial distance from the axis of rotation.

8. Apparatus for rotatably mounting a plurality of workpieces for profiling operations, said apparatus comprising a single plate having an axially directed annular extension and adapted to be secured to and to rotate with a rotatable workshaf-t, an annular cover rigid with said extension and means to permit a partial rotation of said cover, a ring carried between said-extension and said cover and having recesses, a pluralityof radially extending and radially movable plungers passing through said recess and intended to abut against a workpiece, said cover carrying spring means adapted to apply inward radial pressure to said plungers upon rotation of said cover, said plungers being provided with further spring means which are weaker than the first mentioned spring means and are adapted to act radially outwards to hold the plungers away from the workpiece.

THOMASAUBREY KESTELL.

REFERENCE S CITED The following referen ces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,499,773 Hanson July 1, 1924 1,885,095 Hamilton o Oct. 25, 1932 1,901,942 Abramson .Mar..21, 1933 1,917,748 Blazek July .11, .1933 

